The following relates generally to communication links and, more particularly, relates to a system and method for managing communication links using a bi-directional communication protocol.
Bi-directional communication protocols are known in the art. For example, U.S. Pat. No. 5,564,020 described two units, one of which is installed in a computer and one of which is located remotely with respect to the computer, that communicate over an infrared (IR) link. Each unit has a serial number to identify itself and to keep a communication link secure once established. The IR link is established by hitting an initialization switch on each of the two units, at which time they commence transmitting their serial numbers and an acknowledgement process occurs. Once this initialization has occurred and both units have registered with the other unit, only communications from the proper serial number provider are accepted. After the initialization phase, data and commands are sent between the two units in a packetized structure which allows error checking as necessary.
By way of further example, U.S. Pat. No. 5,917,631 describes using a pulse position modulation (PPM) scheme, similar to that described by Garrett in U.S. Pat. No. 4,584,720, to establish a communication link between a remote control and a receiving unit. This PPM scheme uses the position of a single pulse, such as an IR pulse, to indicate a multi—bit value. For example, a sixteen or greater position PPM scheme may be used to encode four-bit hexadecimal data values. In this way, the single pulse may substitute for what otherwise would have been multiple pulses in a simple binary encoding scheme.
By way of still further example, U.S. Pat. No. 5,640,160 describes a PPM modulation protocol where a binary code is divided into 2-bit data units and pulse position modulation is performed on each unit rather than on each bit. In this manner, since a pulse is not formed for each bit, the transmission interval and transmission frame interval for the modulated signal is shortened, thus enabling high speed transmission. In addition, since the width of the pulse does not contain any transmission information, the pulse width is made as short as possible, thereby reducing battery consumption within the transmitter.
While such bi-directional communication protocols do work for their intended purpose, what is needed is an improved system and method for managing bi-directional communication links.